The preset invention relates to alarm systems for multiple dwelling buildings of the type having a central fire alarm system. More particularly, this invention relates to an alarm system for such buildings wherein the alarm condition detectors are located in the individual dwelling units and are connected so as to alert all the building occupants of a detected alarm condition.
It is clear from some of the tradgic occurrences in multiple dwelling buildings, such as apartments, hotels and condominiums, that existing alarm systems are inadequate for the protection of the building inhabitants. In such buildings, individual smoke and/or fire detection systems installed by the inhabitants in their own dwelling units have become more commonplace. In the typical individual alarm system, the detector sounds an audible alarm to warn the occupants of the particular dwelling in which it is located of the presence of smoke or fire. The range of the warning signal is normally limited to the one dwelling, and such individual alarm systems thus fail to indicate the alarm condition to the occupants of the other dwellings in the building.
It has been proposed in some jurisdictions to require individual alarm condition detectors in each dwelling unit of multiple floor, multiple dwelling buildings, and to require the interconnection of the detectors to a common alarm indicator. One specific proposal involves the use of standard fire and/or smoke detectors in each dwelling unit, individually powered by available electrical power in the individual dwellings. For installation in existing dwelling units, such a system requires the running of wires to the detector from the power source within the dwelling unit, as well as the running of wires from each dwelling to the central alarm. Any one of the detectors may be disconnected from the power source or the alarm within the individual dwelling unit without alerting any of the building occupants or maintenance personnel. Moreover, the alarms on each floor of the building must be interconnected to make the system truly effective, thus necessitating the expensive and time consuming process of making an opening through a floor that is typically a concrete slab.
The same problems exist in installing such a system in a new building, but they are somewhat alleviated by the fact that wires can be run within walls, making them less succeptable to disconnection by the occupants. In addition, the openings between floors can be planned and produced during construction. However, the installation costs are still quite high because of the equipment required, and the system is still unreliable from the standpoint of possible disconnection or failure of individual detector units.
Buildings of the type discussed above are presently provided with manual fire alarm boxes. One alarm box is centrally located on each floor of the building and requires manual actuation to sound the alarm. The alarm boxes on each floor are interconnected so as to sound the alarm throughout the building when one box is actuated. Typically, the alarm boxes are connected to a central annunciator which indicates at a central station in the building which particular alarm box has been activated.
Such systems are, of course, of limited value since they do require manual actuation from outside the dwelling unit, placing a burden on the occupants in a situation of possible panic. Moreover, sounding of the alarm is simultaneous with manual actuation of the alarm box, and therefore does not allow for reset without alarm in case of accidental actuation or testing.